This invention relates to valve assemblies and more particularly to valve assemblies for fluid-operated automatic transmissions.
In prior art transmissions, the interconnecting passages or worm tracks for the valving is formed in the transmission housing casting. This surface must be machined along with the remainder of the casting and must be maintained relatively flat to ensure against leakage when the valve body is secured thereto. If there is leakage between the worm tracks caused by porosity or insufficiency of material in the raw casting, the entire case casting must be scrapped.
When design improvements in the control valving occur which require changes in the worm tracks, the old design case must be scrapped or the use of the improvements is delayed until the old casings have been used.